Pluto-Bound Probe Passes Mars’ Orbit

To be dispatched early 2006, the outward bound New Horizons spacecraft will throw new light on distant Pluto and its moon, Charon, as well as Kuiper Belt objects. Image

Credit: Dan Durda

NASA's New
Horizons probe has left the inner planets of the Solar System behind as it streaks
toward a rendezvous with Pluto and its moons.

The spacecraft, billed as NASA's
fastest-flying probe, hurtled past the orbit of Mars - though not the planet
itself - Friday on its way towards a Jupiter flyby and its more distant target Pluto.

"It's
pretty amazing," New Horizons principal investigator Alan
Stern told SPACE.com. "It's
a straight line across the Solar System. There are hardly any curves because
this is so fast."

New Horizons sped past Mars'
orbit some 151 million miles (243 million kilometers) from the Sun at a rate of
about 13 miles (21 kilometers) per second. The red planet, however, trailed
behind the spacecraft at a distance of about 186 million miles (299 million
kilometers), mission managers said, adding that New Horizons was closer to
Earth than Mars.

Six of the probe's seven science
instruments have already been checked
for their health as the spacecraft heads towards Jupiter, where it will use
the giant planet's gravity to boost its way on to Pluto and the icy
object-filled Kuiper Belt.

But first, the spacecraft must pass
through the Asteroid
Belt, which despite its reputation is primarily made up of empty space
rather than a teeming rock field, mission managers said.

"We won't be hit," said Stern, the
executive director of the space science and engineering division at the
Southwest Research Institute in Boulder, Colorado. "We won't even come close
enough to make any useful science observations of asteroids. They're really
very far apart."

New Horizons is expected to fly past
Pluto and its moons July 2015. The spacecraft is due to make its closest
approach to Jupiter on Feb. 28, 2007.

Tariq joined Purch's Space.com team in 2001 as a staff writer, and later editor, covering human spaceflight, exploration and space science. He became Space.com's Managing Editor in 2009. Before joining Space.com, Tariq was a staff reporter for The Los Angeles Times. He is also an Eagle Scout (yes, he has the Space Exploration merit badge) and went to Space Camp four times as a kid and a fifth time as an adult. He has journalism degrees from the University of Southern California and New York University. To see his latest project, you can follow Tariq on Google+, Twitter and on Facebook.